Adaptive Redundancy for Hybrid Processor Reliability

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Solution Overview

Problem

Hybrid systems with mixed architectures, such as IBM System z and commodity accelerators, face reliability issues due to differences in failure rates, leading to effective reliability being lower than the weakest link, as existing systems do not effectively utilize redundancy across heterogeneous components.

Innovation Solution

Implementing a unified, workload-optimized, adaptive redundancy scheme that performs computations multiple times and compares results, using agents to manage workloads across processors with different architectures, and employing modular redundancy to ensure reliability, availability, and serviceability across the system.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If redundancy checking is performed by executing computations multiple times and comparing results, then reliability is improved, but productivity deteriorates due to increased computation time and resource consumption

Engineering Contradiction:
Improveeffective reliabilityVSAvoidcomputation throughput
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The system dynamically adjusts the redundancy level for different workloads based on their reliability requirements. The workload classifier categorizes incoming computations into different reliability classes, and the system applies appropriate redundancy strategies (e.g., no redundancy, single-bit redundancy, or full redundancy) accordingly. This dynamic adaptation allows the system to maintain high reliability for critical workloads while preserving productivity for less critical tasks.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

Different redundancy strategies are applied to different parts of the computation based on their specific requirements. The system applies redundancy checking selectively to certain computational kernels or data types rather than uniformly to all computations. This localized approach ensures that reliability-critical operations receive enhanced protection while non-critical operations proceed with minimal overhead.

Inventive Principle:
Principle #3Local quality

2Productivity

If heterogeneous processors with different architectures are used to improve productivity and cost-effectiveness, then device complexity increases and reliability management becomes more difficult

Engineering Contradiction:
Improvecomputational performanceVSAvoidsystem complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The system employs a universal workload classifier and reliability management framework that operates across all heterogeneous processors regardless of their specific architecture. The classifier uses architecture-agnostic features to categorize workloads, and the redundancy management system applies standardized protocols across different processor types (GPUs, FPGAs, CPUs, ASICs). This universal approach simplifies complexity by providing a consistent interface and management layer over diverse hardware platforms.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The workload classifier acts as an intermediary between the heterogeneous processors and the reliability management system. It translates architecture-specific computation characteristics into a unified classification framework, enabling the reliability system to make informed decisions without needing to understand the intricate details of each processor architecture. This intermediary layer abstracts away the complexity of heterogeneous systems.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If redundant computations are performed on heterogeneous processors with different instruction sets, then reliability is improved, but measurement precision deteriorates due to potential differences in computation results

Engineering Contradiction:
Improveerror detection capabilityVSAvoidcomputation result accuracy
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The system applies different verification strategies based on the computational domain and precision requirements. For integer arithmetic and bitwise operations where exact equality is expected, strict comparison is used. For floating-point operations where minor precision differences are acceptable, the system uses tolerance-based comparison or statistical verification. This localized approach to verification maintains reliability while accommodating the inherent precision characteristics of different computation types.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The system changes the verification parameters based on the workload characteristics. For different data types (integer, floating-point, boolean), different comparison thresholds and verification methods are applied. The workload classifier identifies the precision requirements of each computation and adjusts the redundancy verification parameters accordingly, allowing reliable error detection without falsely flagging legitimate precision variations.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentUS8826069B2Unified, workload-optimized, adaptive RAS for hybrid systems
Publication Date: 2014.09.02 INTERNATIONAL BUSINESS MACHINE CORPORATION
  • US8826069B2 patent drawing
  • US8826069B2 patent drawing
  • US8826069B2 patent drawing

AI summary

A method, system, and computer program product for maintaining reliability in a computer system. In an example embodiment, the method includes managing workloads on a first processor with a first processor architecture by an agent process executing on a second processor with a second processor architecture. The method proceeds by activating redundant computation on the second processor by the agent process. The method continues by performing a same computation from a workload of the workloads at least twice. Finally, the method includes comparing results of the same computation. In this embodiment the first processor is coupled the second processor by a network, and the first processor architecture and second processor architecture are different architectures.